fix: harden typed metrics review findings

scripts/check-metrics-boundaries.py

@@ -10,15 +10,18 @@ from pathlib import Path
 
 MAX_FILES = 20_000
 MAX_FILE_BYTES = 4 * 1024 * 1024
-ALLOWED_ADAPTERS = {
-    "crates/crank-observability/src/instrumentation.rs",
-    "crates/crank-observability/src/prometheus.rs",
-}
 PATTERNS = (
-    re.compile(r"(?<![A-Za-z0-9_])(?:::)?metrics\s*::\s*(?:counter|gauge|histogram|describe_counter|describe_gauge|describe_histogram)\s*!"),
-    re.compile(r"\b(?:pub\s+)?use\s+(?:::)?metrics\s*(?:::\s*(?:\{|counter|gauge|histogram)|\s+as\s+)"),
+    re.compile(
+        r"(?<![A-Za-z0-9_])(?:::)?metrics\s*::\s*(?:counter|gauge|histogram|describe_counter|describe_gauge|describe_histogram|recorder|with_local_recorder|Key|Recorder)\b"
+    ),
+    re.compile(
+        r"\b(?:pub\s+)?use\s+(?:::)?metrics\s*(?:\s+as\s+\w+|::\s*(?:Unit|counter|gauge|histogram|Recorder|Key|\{\s*(?:counter|gauge|histogram|Recorder|Key)))"
+    ),
     re.compile(r"\bextern\s+crate\s+metrics(?:\s+as\s+\w+)?"),
-    re.compile(r"\b(?:set_global_recorder|PrometheusRecorder|DebuggingRecorder)\b"),
+    re.compile(r"\b(?:set_global_recorder|set_boxed_recorder|PrometheusRecorder|DebuggingRecorder|Recorder\s*::|register_counter|register_gauge|register_histogram)\b"),
+)
+DESCRIBE_ONLY = re.compile(
+    r"(?<![A-Za-z0-9_])metrics\s*::\s*describe_(?:counter|gauge|histogram)\s*!"
 )
 
 
@@ -58,25 +61,108 @@ def resolve(root: Path, supplied: str) -> tuple[str, Path] | None:
     return relative.as_posix(), canonical
 
 
+def strip_non_code(text: str) -> str:
+    """Remove comments and literals while preserving newlines and token separation."""
+    output = list(text)
+    index = 0
+    block_depth = 0
+    while index < len(text):
+        if block_depth:
+            if text.startswith("/*", index):
+                block_depth += 1
+                output[index:index + 2] = "  "
+                index += 2
+            elif text.startswith("*/", index):
+                block_depth -= 1
+                output[index:index + 2] = "  "
+                index += 2
+            else:
+                if text[index] != "\n":
+                    output[index] = " "
+                index += 1
+            continue
+        if text.startswith("//", index):
+            end = text.find("\n", index)
+            end = len(text) if end < 0 else end
+            for cursor in range(index, end):
+                output[cursor] = " "
+            index = end
+            continue
+        if text.startswith("/*", index):
+            block_depth = 1
+            output[index:index + 2] = "  "
+            index += 2
+            continue
+        raw = re.match(r"(?:br|r)(?P<hashes>#{0,16})\"", text[index:])
+        if raw:
+            terminator = '"' + raw.group("hashes")
+            end = text.find(terminator, index + raw.end())
+            end = len(text) if end < 0 else end + len(terminator)
+            for cursor in range(index, end):
+                if text[cursor] != "\n":
+                    output[cursor] = " "
+            index = end
+            continue
+        prefix = 1 if text.startswith("b\"", index) or text.startswith("b'", index) else 0
+        quote_index = index + prefix
+        is_string = quote_index < len(text) and text[quote_index] == '"'
+        is_char = quote_index < len(text) and text[quote_index] == "'" and re.match(
+            r"'(?:\\.|[^\\'\n])'", text[quote_index:]
+        )
+        if is_string or is_char:
+            quote = text[quote_index]
+            end = quote_index + 1
+            escaped = False
+            while end < len(text):
+                char = text[end]
+                end += 1
+                if escaped:
+                    escaped = False
+                elif char == "\\":
+                    escaped = True
+                elif char == quote:
+                    break
+            for cursor in range(index, end):
+                if text[cursor] != "\n":
+                    output[cursor] = " "
+            index = end
+            continue
+        index += 1
+    return "".join(output)
+
+
+def is_test_path(logical: str) -> bool:
+    parts = Path(logical).parts
+    return bool(parts and parts[0] == "tests") or (
+        len(parts) >= 4 and parts[0] in {"apps", "crates"} and parts[2] == "tests"
+    )
+
+
 def scan(logical: str, path: Path) -> bool:
     if logical.startswith("crates/crank-metrics/"):
         return False
-    if "/tests/" in logical or logical.startswith("tests/"):
+    if is_test_path(logical):
         return False
     try:
         if path.stat().st_size > MAX_FILE_BYTES:
             return True
-        text = path.read_text(encoding="utf-8")
+        text = strip_non_code(path.read_text(encoding="utf-8"))
     except (OSError, UnicodeError):
         return True
-    for pattern in PATTERNS:
-        if not pattern.search(text):
-            continue
-        if logical in ALLOWED_ADAPTERS and pattern is PATTERNS[0] and "describe_" in pattern.search(text).group(0):
-            continue
-        if logical == "crates/crank-observability/src/prometheus.rs" and pattern is PATTERNS[3]:
-            continue
-        return True
+    matches = [match for pattern in PATTERNS for match in pattern.finditer(text)]
+    if not matches:
+        return False
+    if logical == "crates/crank-observability/src/instrumentation.rs":
+        residual = DESCRIBE_ONLY.sub("", text)
+        residual = re.sub(r"\buse\s+metrics\s*::\s*Unit\s*;", "", residual)
+        return any(pattern.search(residual) for pattern in PATTERNS)
+    if logical == "crates/crank-observability/src/prometheus.rs":
+        allowed = ("PrometheusRecorder",)
+        residual = text
+        for token in allowed:
+            residual = residual.replace(token, "")
+        return any(pattern.search(residual) for pattern in PATTERNS)
+    return True
     return False
 
 
@@ -91,6 +177,9 @@ def main(argv: list[str]) -> int:
     if len(supplied) > MAX_FILES:
         print("error: metrics boundary input limit exceeded", file=sys.stderr)
         return 1
+    if args.files is not None and not supplied:
+        print("error: metrics boundary explicit file list is empty", file=sys.stderr)
+        return 1
     violations: list[str] = []
     for index, item in enumerate(sorted(set(supplied))):
         resolved = resolve(root, item)